1. Field of the Invention
The present invention relates to a method of producing 2',3'-dideoxyinosine from 2',3'-dideoxyadenosine.
2. Description of the Related Art
2',3'-Dideoxyinosine has a potent anti-viral activity and is thus expected to be a therapeutic agent for viral diseases such as influenza, AIDS, etc.
As a method for synthesis of dideoxynucleosides such as 2'3'-dideoxyinosine, etc. which are conventionally known, deoxygenation of nucleosides at the 2'- or 3'-position is known as is reported in Chem. Pharm. Bull., 22, 128 (1974). However, only a few such cases are reported because a protective group must be introduced prior to the reaction, the reaction occurs at the 2'- or 3'-position with difficulty due to serious steric hindrance, and vigorous reaction conditions or reactants cannot be used due to unstability of nucleosides under severe conditions. Thus, no industrially satisfactory method has been established.
Against this background, the present inventors previously developed a method of producing 2',3'-dideoxynucleosides such as 2',3'-dideoxyinosine, 2',3'-dideoxyadenosine, etc. from 2',3'-dideoxyuridine or 2,3-dideoxyribose-1-phosphate by the action of microorganisms (Japanese Patent Application No. 62-149893).
However, this method is effective but there remains a defect in that the yield is somewhat poor in the case of producing 2',3'-dideoxyinosine.
Furthermore, an attempt to convert 2',3'-dideoxyadenosine into 2',3'-dideoxyinosine using animal organ-derived adenosine deaminase was made (Biochim. Biophys. Acta, 566 (2), 259 (1979)) but since the enzyme is derived from an animal source, the method is not suited from the viewpoints of both cost and supply.
Conventional chemical methods for synthesizing 2',3'-dideoxyinosine are all defective in that many reaction steps are involved and the yield is poor.